1. Field of the Invention
The present invention relates to a process for removing heat from a Fischer-Tropsch (F-T) slurry reactor and a system implemented by the process for removing heat from a (F-T) slurry reactor.
2. Description of the Related Art
The F-T reaction is an exothermic reaction requiring the need for heat removal to maintain the internal reactor temperature at the desired operating temperature. Heat Removal/Temperature control in a F-T reactor is very important for maintaining catalyst performance. Heat removal from a slurry F-T reactor is typically accomplished by an internal or external heat transfer system. The heat transfer system typically consists of heat transfer tubes with a cooling medium (i.e. water) circulating internally. Heat is transferred from the slurry to the cooling medium. In the case of water as a cooling medium, steam is generated.
The required heat removal adds significant capital to the cost of the reactor in the form of additional metal. There are many design approaches that can be applied to address the heat removal requirement from the F-T Reactor. In one design, split-zones (with a zone being a cylinder with cross section equal to the reactor internal diameter and of a certain height, see FIG. 1 for illustration) may be used to promote efficient heat removal. In another design a steam drum may be elevated above the heat transfer tubes to eliminate vaporization in the downcomer and promote efficient heat transfer in the risers. In either approach, forced or natural circulation could be considered.
To this end, although various reactor designs may be utilized to remove heat, further improvements are desirable to remove the need for multiple zones and elevated drums. It is to such a reactor design that the present invention is directed.